Dr. Thomas E. Mattingly, 77, a Washington native who practiced medicine here for 45 years, died Wednesday of complications following surgery at Holy Cross Hospital.

Dr. Mattingly was at the same time an outspoken oppent of the American Medical Association and of socialized medicine, frequently attacking both in the hundreds of letters he wrote to the editors of Washington's newspapers.

In those letters, many of which were published, Dr. Mattingly strongly advocated a national health insurance plan, which would allow individuals to select their own physicians, as an alternative to socialized medicine.

Dr. Mattingly was a graduate of McKinley High School and the Georgetown University Medical School, and served as a medical aide in France during World War I. During the Second World War he served for three years in the Southwest Pacific with the Army Medical Corps and left the service a Lieutenant Colonel at the end of the war.

In addition to tending to his private patients, Dr. Mattingly served for the 13 years prior to his retirement in 1971 as medical director of the National Lutheren Home for the Aged in northeast Washington.

He is survived by his wife, Grace L., of the home in Wheaton; two sons, Dr. Thomas E., Jr., of Mt. Holly, N.J. and Richard C., of Chevy Chase; two daughters, Grace Clarke, of New Carrollton, and Phyllis J. Evans, of Bethesda; a sister, Evelyn St. Clair, of Silver Spring; and 18 grandchildren.